Separation by high-performance liquid chromatography of (3R)- and (3S)-β-leucine as diastereomeric derivatives

Aberhart, D. John; Cotting, Jacques-Alain; Lin, Horng-Jau

doi:10.1016/0003-2697(85)90056-9

Cited by 27 publications

(12 citation statements)

References 17 publications

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“…Optical isomers of alanine were determined as described previously (Aberhart et al, 1985;Marfey, 1984). Briefly, extracellular fractions were extracted with an equal volume of chloroform by vigorous shaking for 15 min, followed by centrifugation (12 000 g, 5 min, 23 C).…”

mentioning

confidence: 99%

Secretion of d-alanine by Escherichia coli

et al. 2016

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Escherichia coli has an L-alanine export system that protects the cells from toxic accumulation of intracellular L-alanine in the presence of L-alanyl-L-alanine (L-Ala-L-Ala). When a DadA-deficient strain was incubated with 6.0 mM L-Ala-L-Ala, we detected L-alanine and D-alanine using highperformance liquid chromatography (HPLC) analysis at a level of 7.0 mM and 3.0 mM, respectively, after 48 h incubation. Treatment of the culture supernatant with D-amino acid oxidase resulted in the disappearance of a signal corresponding to D-alanine. Additionally, the culture supernatant enabled a D-alanine auxotroph to grow without D-alanine supplementation, confirming that the signal detected by HPLC was authentic D-alanine. Upon introduction of an expression vector harbouring the alanine racemase genes, alr or dadX, the extracellular level of Dalanine increased to 11.5 mM and 8. indicate that E. coli has a transport system(s) that exports D-alanine and that this function is most likely modulated by proton electrochemical potential.

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confidence: 99%

Secretion of d-alanine by Escherichia coli

et al. 2016

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“…For the model structure apicidin (1), as an example, it is known that multiple conformations stem from cis-trans isomerism of the pipecolic acid building block [69,71]. HPLC purification of the compounds resulted in sharp peaks indicating that one predominant isomer was synthesized [72][73][74]. However, NMR-spectra of the cyclic tetramers corroborated the formation of several conformers for almost every macrocycle (supplemental, Table S6).…”

Section: Multiconformational Equilibrium Detected By Nmrmentioning

confidence: 99%

“…Influencing factors are i.a. side chains, solvent effects, and temperature [71,72]. For the model structure apicidin (1), as an example, it is known that multiple conformations stem from cis-trans isomerism of the pipecolic acid building block [69,71].…”

Section: Multiconformational Equilibrium Detected By Nmrmentioning

confidence: 99%

Macrocyclic Tetramers – Structural Investigation of Peptide-Peptoid Hybrids

Herlan¹,

Sonnefeld²,

Glöge³

et al. 2021

Preprint

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The determination of the three-dimensional structure is a key step for the identification of new targets as well as the rational design of bioactive compounds. Herein, we report the synthesis and the structural elucidation of novel tetrameric macrocycles. Measurements were taken in solid and solution states with the help of X-ray scattering and NMR spectroscopy. The investigations made will help to find diverse applications for this new, promising compound class.

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“…This was done essentially as described by Aberhart et al [16]. Amp (0.5/zmol) in 1 M NaHCO3 (40/zl) was allowed to react with N-(2,4-dinitro-5-fluorophenyl)-L-valinamide (0.7 /zmol) in acetone (20 /zl) for 1 h at 40 ~ After the addition of 2 M HC1 (20/zl), the mixture was centrifuged (12 000xg for 3 min) and a portion (10/zl) was taken for HPLC.…”

Section: Determination Of Enantiomeric Puritymentioning

confidence: 99%